The present invention relates to a crane, in particular to a lattice mast crane; having a bottom hook block with a load suspension means, in particular a load hook.
When raising large loads at great heights, the robustness of the hoisting system toward external influences, in particular attacking wind forces, plays a decisive role. The large loads to be raised have a large surface and consequently offer a large exposed surface to the wind forces. The engaging forces result in a swaying of the load or an oscillating of the hook, which can have the consequence of an unstable hoist system. For safety reasons, limits are defined for maximum permitted wind speeds up to which a planned hoist may be carried out at all.
The robustness of the system with respect to the attacking wind forces is also a decisive criterion in the installation of the suspended load at a great height since an alignment of the load at the installation height which is as precise and as stable as possible is desirable here.
Since each individual hoist or each installation causes substantial equipment and operating costs, one objective in the development of such hoisting systems is the expansion of the maximum permitted limits for the wind speeds. If the limits can be made more flexible and more tolerant, a planned hoist can be carried out faster and less expensively.
A possible solution approach which allows a reliable alignment of the large loads susceptible to the wind in the installation of wind turbines, in particular of the suspended rotors or rotor blades, is known from the prior art. DE 20 2006 015 189 U1 proposes for this purpose the use of a frame for taking up a rotor blade, said frame being connected to the telescopic crane via a stabilizing guy rope connection. However, the apparatus disclosed therein relates specifically to the hoisting or the installation of rotor blades.